By sandwiching a CoFeB ferromagnetic layer between Ta and Pt heavy metals with an opposite spin Hall angle, spin currents of the same polarity are transmitted from both interfaces of the Ta/CoFeB/Pt trilayer to the CoFeB layer simultaneously. Here, we investigated the spin-orbit torque, magnetization dynamics, and interface spin transmission efficiency of the trilayer heterostructure by spin-torque ferromagnetic resonance. A large effective spin Hall angle, substantially larger than both Ta and Pt, was obtained in the Ta/CoFeB/Pt stack. The thickness-dependence study showed that with the reducing of CoFeB thickness, Gilbert damping enhances by spin pumping and spin Hall angle increases by the spin Hall effect and the Rashba effect. Furthermore, the spin transparency derived from effective spin mixing conductance was 0.63 ± 0.07 and 0.48 ± 0.02 at the CoFeB/Pt and Ta/CoFeB interfaces, respectively. Hence, the spin Hall angle could be further enhanced by improving the spin transmission efficiency at the interface. Our method of increasing spin-orbit torque through stack engineering would have potential applications in domain wall racetrack memory, logic gates, and magnetic tunnel junctions.By sandwiching a CoFeB ferromagnetic layer between Ta and Pt heavy metals with an opposite spin Hall angle, spin currents of the same polarity are transmitted from both interfaces of the Ta/CoFeB/Pt trilayer to the CoFeB layer simultaneously. Here, we investigated the spin-orbit torque, magnetization dynamics, and interface spin transmission efficiency of the trilayer heterostructure by spin-torque ferromagnetic resonance. A large effective spin Hall angle, substantially larger than both Ta and Pt, was obtained in the Ta/CoFeB/Pt stack. The thickness-dependence study showed that with the reducing of CoFeB thickness, Gilbert damping enhances by spin pumping and spin Hall angle increases by the spin Hall effect and the Rashba effect. Furthermore, the spin transparency derived from effective spin mixing conductance was 0.63 ± 0.07 and 0.48 ± 0.02 at the CoFeB/Pt and Ta/CoFeB interfaces, respectively. Hence, the spin Hall angle could be further enhanced by improving the spin transmission efficiency at the int...

中文翻译：

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工程磁性异质结构以获得自旋轨道扭矩装置的大自旋霍尔效率

通过将 CoFeB 铁磁层夹在具有相反自旋霍尔角的 Ta 和 Pt 重金属之间，相同极性的自旋电流从 Ta/CoFeB/Pt 三层的两个界面同时传输到 CoFeB 层。在这里，我们通过自旋扭矩铁磁共振研究了三层异质结构的自旋轨道扭矩、磁化动力学和界面自旋传输效率。在 Ta/CoFeB/Pt 堆叠中获得了大的有效自旋霍尔角，远大于 Ta 和 Pt。厚度相关性研究表明，随着 CoFeB 厚度的减小，吉尔伯特阻尼通过自旋泵浦增强，自旋霍尔角通过自旋霍尔效应和拉什巴效应增加。此外，来自有效自旋混合电导的自旋透明度为 0.63 ± 0.07 和 0.48 ± 0。02 分别在 CoFeB/Pt 和 Ta/CoFeB 界面处。因此，可以通过提高界面处的自旋传输效率来进一步增强自旋霍尔角。我们通过堆栈工程增加自旋轨道扭矩的方法将在畴壁跑道存储器、逻辑门和磁性隧道结中具有潜在应用。通过在具有相反自旋霍尔角的 Ta 和 Pt 重金属之间夹入 CoFeB 铁磁层，自旋电流相同极性的极性同时从 Ta/CoFeB/Pt 三层的两个界面传输到 CoFeB 层。在这里，我们通过自旋扭矩铁磁共振研究了三层异质结构的自旋轨道扭矩、磁化动力学和界面自旋传输效率。大的有效自旋霍尔角，远大于 Ta 和 Pt，在 Ta/CoFeB/Pt 堆栈中获得。厚度相关性研究表明，随着 CoFeB 厚度的减小，吉尔伯特阻尼通过自旋泵浦增强，自旋霍尔角通过自旋霍尔效应和拉什巴效应增加。此外，在 CoFeB/Pt 和 Ta/CoFeB 界面处，源自有效自旋混合电导的自旋透明度分别为 0.63 ± 0.07 和 0.48 ± 0.02。因此，通过提高自旋传输效率可以进一步提高自旋霍尔角... CoFeB/Pt 和 Ta/CoFeB 界面分别为 48 ± 0.02。因此，通过提高自旋传输效率可以进一步提高自旋霍尔角... CoFeB/Pt 和 Ta/CoFeB 界面分别为 48 ± 0.02。因此，通过提高自旋传输效率可以进一步提高自旋霍尔角...